This application requests renewal of a grant to provide state-of-the art post-doctoral training in molecular imaging. Despite a clear and growing need of the field, few opportunities now exist for providing broad, in depth, and interdisciplinary training for individuals to develop and validate novel methods for non-invasively sensing molecular and cellular processes in vivo and ultimately in patients. The program is based at the Center for Molecular Imaging Research (CMIR) at Massachusetts General Hospital and includes members of three other Harvard Hospitals as well as basic science faculty of Harvard Medical School. Former trainees are now independent investigators in academia, are associated with large pharmaceutical divisions involved inoncology drug development or are in advanced medical training. This training grant now includes 28 research faculty who were selected on the basis of proven scientific achievement, focus on basic cancer processes, mentoring skills, research program participation and the feedback and experience of postdoctoral fellows. The selected faculty is highly accomplished and includes 16 Full Professors, 7 Associate Professors,4 Assistant Professors and 1 Instructor. The faculty has over 100 extramural research grants that directly address issues of cancer diagnosis and therapy. The faculty has successfully supervised over 300 pre and postdoctoral fellows in various aspects of basic and clinical research. We have also developed successful programs in minority recruitment, scientific integrity and cancer related training and research. We feel strongly that, with our current faculty, enhanced facilities, scope of supported research, and past accomplishments, we can continue to provide an outstanding research environment for the next generation of clinicians and scientists trained in molecular imaging.